My son has a Winchester SuperX2 that is a biatch to get the barrel off. Where the barrel goes into the receiver has always been snug but now us requires tools to separate and put back together. Nothing seems to be bent or damaged. It's like the metal has just swelled. I clean it to the point of shining, so I know it isn't dirt or grime. I only use a tiny amount of fine oil on it.

WTF? Any of you hands had this issue with a shotgun? I hate to spend money at the gunsmith but I would hate to break something, pounding it apart and back together, even more. The gun has otherwise been trouble free.